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arXiv 2007.09926cond-mat.mes-hallcond-mat.mtrl-sci
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封装双层Jacutingaite中的门可调非平衡Kane-Mele模型

Gate-tunable imbalanced Kane-Mele model in encapsulated bilayer jacutingaite

Louk Rademaker, Marco Gibertini

摘要:

本文从第一性原理出发,研究了自由、封端和包封的双层紫顶云母Pt $_2$ HgSe $_3$。而独立的双层是一个大的间隙平凡绝缘体,我们发现,封装的结构有一个小的平凡的间隙,由于亚晶格对称性破缺和亚晶格依赖的次近邻跳跃之间的竞争。当施加小的垂直电场时,封装的双层经历朝向量子自旋霍尔绝缘体的拓扑转变。我们发现,这种拓扑转变可以定性地理解,通过建模的两个层的非耦合和描述的不平衡凯恩-梅勒模型,考虑到子晶格的不平衡和相应的反转对称性破缺在每一层。在这张照片中,双层jacutingaite经历了从0+0状态的转变,其中每一层都是平凡的,到0+1状态,其中依赖于Rashba类自旋轨道耦合的不寻常拓扑状态只出现在其中一层中。

英文摘要:

We study free, capped and encapsulated bilayer jacutingaite Pt$_2$HgSe$_3$ from first principles. While the free standing bilayer is a large gap trivial insulator, we find that the encapsulated structure has a small trivial gap due to the competition between sublattice symmetry breaking and sublattice-dependent next-nearest-neighbor hopping. Upon the application of a small perpendicular electric field, the encapsulated bilayer undergoes a topological transition towards a quantum spin Hall insulator. We find that this topological transition can be qualitatively understood by modeling the two layers as uncoupled and described by an imbalanced Kane-Mele model that takes into account the sublattice imbalance and the corresponding inversion-symmetry breaking in each layer. Within this picture, bilayer jacutingaite undergoes a transition from a 0+0 state, where each layer is trivial, to a 0+1 state, where an unusual topological state relying on Rashba-like spin orbit coupling emerges in only one of the layers.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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